"And we will call it...this land..."
^ picture-perfect example of relying waaaaaaay too much on Ne.
Mal could be ESTP. Definitely P, definitely E, probably T.
River and Simon are the classic INTP/INTJ dichotomy, as kids. As adults, it's even more so... Simon might seem S or F but that's what decades of schooling does to INTJs. River's uncontrollable emotions are more indicative of underdeveloped (or rather, damaged) F than of F preference.
Ironic that this pattern is staring you in the face and you're not seeing itPatterns, particularly the screamingly obvious pattern clues constantly uttered by his sister, can stare him right in the face and he will stare back slack-jawed, holding on for some further opportunity to be obsequiously snotty or suffocatingly caring.